Diamond-silicon hybrid integrated heat spreader

ABSTRACT

An electronic device includes a die further having a first major surface, and a second major surface. The electronic device also includes a plurality of connectors associated with the first major surface of the die, and an integrated heat spreader in thermally conductive relation with the second major surface of the die. The integrated heat spreader also has a layer of silicon, and a layer of diamond attached to the layer of silicon. The first major surface of the die attached to a printed circuit board. A method for forming a heat dissipating device includes placing a layer of diamond on a silicon substrate, and thinning the silicon substrate. The substrate is diced to form a plurality of heat dissipating devices sized to form a thermally conductive connection to a die. A surface of the silicon substrate is placed in thermal communication with a source of heat.

RELATED APPLICATION(S)

This application is a Divisional of U.S. application Ser. No. 10/610,347filed on Jun. 30, 2003 which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to a heat dissipation system and methodfor an integrated circuit assembly. More specifically, the presentinvention relates to a diamond-silicon hybrid integrated heat spreader.

BACKGROUND OF THE INVENTION

The semiconductor industry has seen tremendous advances in technology inrecent years that have permitted dramatic increases in circuit densityand complexity, and equally dramatic decreases in power consumption andpackage sizes. Present semiconductor technology now permits single-chipmicroprocessors with many millions of transistors, operating at speedsof tens (or even hundreds) of MIPS (millions of instructions persecond), to be packaged in relatively small, air-cooled semiconductordevice packages. As integrated circuit devices, microprocessors andother related components are designed with increased capabilities andincreased speed, additional heat is generated from these components. Aspackaged units and integrated circuit die sizes shrink, the amount ofheat energy given off by a component for a given unit of surface area isalso on the rise. The majority of the heat generated by a component,such as a microprocessor, must be removed from the component to keep thecomponent at an operating temperature. If the heat generated is notremoved from the component, the heat produced can drive the temperatureof the component to levels that result in failure of the component. Insome instances, the full capability of certain components can not berealized since the heat the component generates at the full capabilitywould result in failure of the component.

A seemingly constant industry trend for all electronic devices, andespecially for personal computing, is to constantly improve products byadding increased capabilities and additional features. For example, theelectronics industry has seen almost a 50 fold increase in processingspeed over the last decade. Increasing the speed of a microprocessorincreases the amount of heat output from the microprocessor.Furthermore, as computer related equipment becomes smaller and morepowerful, more components are being used as part of one piece ofequipment. As a result, the amount of heat generated on a per unitvolume basis is also on the increase. A portion of an amount of heatproduced by semiconductors and integrated circuits within a device mustbe dissipated to prevent operating temperatures that can potentiallydamage the components of the equipment, or reduce the lifetime of theindividual components and the equipment.

An integrated circuit has a front side and a back side. The front sideof the integrated circuit includes leads for inputs, outputs and powerto the integrated circuit. Leads include many forms, including pins andballs in a ball grid array. The leads of an integrated circuit areattached to pads on another device such as a printed circuit board. Forexample, an integrated circuit that includes a die having amicroprocessor therein has a front side that is attached to the pads ona motherboard. A heat sink is attached to the back side of theintegrated circuit. In other words, the heat sink is attached to theback side major surface and extends away from a printed circuit board towhich the integrated circuit is mounted. Therefore, generally a majorportion of the heat generated is extracted from the back side of theintegrated circuit with the die therein.

There is generally a limitation on the amount of heat that can beextracted from the back side of the integrated circuit die, because ofthe thermal resistance induced by the thermal interface materials (suchas a silicon die, any thermal grease, adhesives or solders) used betweenthe back side of the integrated circuit die and the heat sink. Most heatsinks are formed from copper or aluminum. The materials used currentlyas heat sinks have a limited ability to conduct heat. Relatively largefin structures are also provided to increase the amount of heat removedvia conduction. Fans are also provided to move air over the finstructures to aid in the conduction of heat. Increasing the size of thefin structure increases the volume of the heat sink, and generally alsoincreases the stack height of the heat sink. In many electronic devices,the overall size of the heat sink is generally limited by volumeconstraints of the housing. For example, in some mobile products such aslaptop computers and ultra-mobile computers, small stack heights arerequired.

The use of aluminum and copper heat sinks with fin structures are nowapproaching their practical limits for removal of heat from a highperformance integrated circuit, such as the integrated circuits thatinclude dies for microprocessors. When heat is not effectivelydissipated, the dies develop “hot spots” or areas of localizedoverheating. Ultimately, the circuitry within the die fails. When thedie fails, the electrical component also fails.

In some instances, aluminum and copper heat sinks are replaced with adiamond heat sink. Diamond heat sinks are difficult to manufacture. Oneaspect of a diamond heat sink is that one major surface of the heat sinkmust be ground smooth to provide a good thermal connection at a thermalinterface. Grinding or smoothing diamond is time consuming. Diamond heatsinks are also expensive.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the appended claims.However, a more complete understanding of the present invention may bederived by referring to the detailed description when considered inconnection with the figures, wherein like reference numbers refer tosimilar items throughout the figures, and:

FIG. 1 is a top view of a printed circuit board having a component witha diamond-silicon hybrid integrated heat spreader, according to anembodiment of this invention.

FIG. 2 illustrates a component having a diamond-silicon hybridintegrated heat spreader attached to the die of an integrated circuit,according to an embodiment of this invention.

FIG. 3A illustrates a schematic side view of a silicon substrate orwafer at the beginning of a process for forming a diamond-silicon hybridintegrated heat spreader, according to an embodiment of this invention.

FIG. 3B illustrates a schematic side view of a silicon substrate orwafer after a diamond layer has been deposited thereon during theprocess for forming a diamond-silicon hybrid integrated heat spreader,according to an embodiment of this invention.

FIG. 3C illustrates a schematic side view of a silicon substrate orwafer after a portion of the silicon has been removed during the processfor forming a diamond-silicon hybrid integrated heat spreader, accordingto an embodiment of this invention.

FIG. 4 is a graph of the junction-to-air thermal resistance of anintegrated circuit on a diamond silicon hybrid heat spreader versus thediamond layer thickness in microns for a die attached to adiamond-silicon hybrid integrated heat spreader, according to anembodiment of this invention.

FIG. 5 is a flow diagram of the process for forming a diamond-siliconhybrid integrated heat spreader, according to an embodiment of thisinvention.

FIG. 6 illustrates a diamond-silicon hybrid integrated heat spreaderattached to the die of an integrated circuit, according to anotherembodiment of this invention.

FIG. 7 is a graph of the bonding strength of a silicon to silicon bondversus the bonding temperature according to an embodiment of thisinvention.

The description set out herein illustrates the various embodiments ofthe invention, and such description is not intended to be construed aslimiting in any manner.

DETAILED DESCRIPTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which are shown by way of illustration specific embodiments inwhich the invention can be practiced. The embodiments illustrated aredescribed in sufficient detail to enable those skilled in the art topractice the teachings disclosed herein. Other embodiments can beutilized and derived therefrom, such that structural and logicalsubstitutions and changes can be made without departing from the scopeof present inventions. The following detailed description, therefore, isnot to be taken in a limiting sense, and the scope of variousembodiments of the invention is defined only by the appended claims,along with the full range of equivalents to which such claims areentitled.

FIG. 1 is a top view of a printed circuit board 100 having a componentwith a diamond-silicon hybrid integrated heat spreader, according to anembodiment of the invention. The printed circuit board (“PCB”) 100 is amulti-layer plastic board that includes patterns of printed circuits onone or more layers of insulated material. The patterns of conductorscorrespond to wiring of an electronic circuit formed on one or more ofthe layers of the printed circuit board 100. The printed circuit board100 also includes electrical traces 110. The electrical traces 110 canbe found on an exterior surface 120 of the printed circuit board 100 andalso can be found on the various layers within the printed circuit board100. Printed circuit boards also include through holes (not shown inFIG. 1) which are used to interconnect traces on various layers of theprinted circuit board 100. The printed circuit board 100 can alsoinclude planes of metallized materials such as ground planes, powerplanes, or voltage reference planes (not shown in FIG. 1).

The printed circuit board 100 is also populated with various components130, 132, 134, 136, 138. The components 130, 132, 134, 136, 138 caneither be discreet components or semiconductor chips which includethousands of transistors. The components 130, 132, 134, 136, 138 can useany number of technologies to connect to the exterior surface 120 of theprinted circuit board 100. For example, pins may be inserted into platedthrough holes or pins may be extended through the printed circuit board100. An alternative technology is surface mount technology where anelectrical component, such as component 136, mounts to an array of padson the exterior surface 120 of the printed circuit board 100. Forexample, component 136 could be a ball grid array package or device thathas an array of balls or bumps that interact or are connected to acorresponding array of pads on the exterior surface 120 of the printedcircuit board 100. The printed circuit board 100 can also includeconnectors for making external connections to other electrical orelectronic devices. The component 136 is a central processing chip ormicroprocessor. The component 136 includes a diamond-silicon hybridintegrated heat spreader 150. The diamond-silicon hybrid integrated heatspreader 150 is attached to the back side of the component 136. Thediamond-silicon hybrid integrated heat spreader 150 removes heat fromthe component 136. The diamond-silicon hybrid integrated heat spreader150 may also be referred to as a heat sink 150 or an integrated heatsink 150 within this document. It should be noted that thediamond-silicon hybrid integrated heat spreader 150 can be attached toany of the components 130, 132, 134, 136, 138 and is not limited toattachment only to the component 136 which is a central processing chipor microprocessor. Generally, however, a microprocessor is a componentthat generates the most heat and therefore most likely to have a heatsink thereon.

As shown in FIG. 1, the printed circuit board 100 includes a first edgeconnector 140 and a second edge connector 142. As shown in FIG. 1 thereare external traces, such as electrical trace 110, on the externalsurface 120 of the printed circuit board 100 that connect to certain ofthe outputs associated with the first edge connector 140. Other tracesthat connect with the edge connectors 140, 142 will have traces internalto the printed circuit board 100.

FIG. 2 illustrates a component 136 having a diamond-silicon hybridintegrated heat spreader 150 attached to the die 210 of an integratedcircuit 212, according to an embodiment of this invention. Thediamond-silicon hybrid integrated heat spreader 150 may also be termed aheat dissipation device. The heat dissipation device, or diamond-siliconhybrid integrated heat spreader 150, includes a silicon substrate 220and a layer of diamond 230 attached to the silicon substrate 220. Thelayer of diamond 230 is deposited on the silicon substrate 220. In someembodiments the deposited diamond is a film having a thickness ofapproximately 25 to 400 microns. In another embodiment, the diamondfilm, has a thickness in the range of 50 to 300 microns. In still otherembodiments the diamond film forming the layer of diamond 230 has athickness in the range of 100 to 200 microns.

The diamond layer 230 is deposited on the silicon layer or siliconsubstrate 220, using a chemical vapor deposition (CVD) process. In oneembodiment the CVD process is plasma enhanced. The diamond layer 230 isdeposited on a wafer-sized silicon substrate 220 in a vapor depositionchamber. Within the vapor deposition chamber the pressure is 20-50 Torrand the temperature of the chamber is in the range of 800 to 1000° C.The process gasses included within the chamber are methane and hydrogen.The methane levels typically vary in the range of 0.5 to 5%. The diamondlayer 230 is deposited onto the wafer-sized silicon substrate 220 at adeposition rate of approximately 10 to 50 microns per hour. As a resultit takes from 2 to 10 hours to deposit a diamond film or diamond layer230 that is 100 microns thick.

Plasma is activated in the chamber using any of a variety of techniques,including a radio-frequency induced glow discharge, DC arc jets, amicrowave CVD or other plasma source. Plasma activation is used toinduce a plasma field in the deposition gas and provides for lowtemperatures as well as good film uniformity and through put. The layerof silicon 220 has a thickness in the range from 1 to 40 microns. Inother embodiments, the layer of silicon 220 is in the range of 1 to 20microns, and in still further embodiments, the layer of silicon 220 isin the range of 1 to 10 microns.

The silicon substrate, or layer of silicon 220, has a first majorsurface 221 to which the diamond film or diamond layer 230 is attached.The diamond or the silicon substrate 220 also has a second major surface222. The second major surface 222 of the silicon substrate 220 istypically smoothed so that when attached to a surface 211 of the die 210a connection having a low resistivity to the flow of heat will beformed. In some embodiments the surface 222 of the silicon substrate 220is removed using a grinding process. The grinding process results in asmooth surface 222 associated with the silicon substrate 220. Thegrinding process also removes a portion of the silicon substrate 220from the wafer-sized silicon substrate 220.

As shown in FIG. 2, the wafer-sized silicon substrate 220 and thediamond layer 230 have been cut or diced or singulated to sizes whichcorrespond to the surface area of the surface 211 of the die 210. Theheat dissipation device for diamond-silicon integrated heat spreader 150also includes a thermal interface layer 240. The thermal interface layer240 may be a metal, such as copper, or a thermal grease. The thermalinterface material 240 is used to connect the heat dissipation device ordiamond-silicon integrated heat spreader 150 to the die 210. The thermalinterface material 240 fills in any air pockets or other spaces that mayoccur when the heat dissipation device or diamond-silicon integratedheat spreader 150 is placed onto the surface 211 of the die 210. Whenthe heat dissipation device or diamond-silicon integrated heat spreader150 is placed onto the surface 211 of the die 210, the die 210 and theheat dissipation device or diamond-silicon integrated heat spreader 150are placed in thermally conductive relation with one another.

The heat dissipation device or diamond-silicon integrated heat spreader150 is attached to the surface 211 to form an integrated heat sink orheat spreader with the die 210. The surface 211 of the die is alsoreferred to as the back side surface of the die 210. The die 210 alsoincludes a set of leads which may be in one of several forms. As shownin FIG. 2, the leads are balls 214, which are placed in an array. Thistype of package is referred to as a ball grid array package. Theindividual balls 214 of the ball grid array electrically contact pads onan organic LAN grid array (OLGA) 250. OLGA is a composite material madeof multiple layers of conductive material such as copper and an organicmaterial. The multiple layers of copper are embedded inside the organicmaterial to provide electrical coupling between the integrated circuitry212 within the die 210 and the electrical circuitry within OLGA 250. TheOLGA 250 completes the package. The OLGA 250 includes pins or balls 254which are used to attach to a printed circuit board 100 (shown in FIG.1).

FIGS. 3A, 3B and 3C show various steps in a process forming adiamond-silicon hybrid integrated heat spreader 150. FIG. 3A illustratesa schematic side view of a silicon substrate or wafer 2200 at thebeginning of a process for forming a diamond-silicon hybrid integratedheat spreader, according to an embodiment of this invention. The siliconsubstrate 2200 is a wafer of silicon which is processed to ultimatelyform the diamond-silicon hybrid integrated heat spreader 150 shown inFIGS. 1 and 2. The silicon substrate 2200 can be a low-cost substratefabricated using a polycrystalline silicon wafer.

FIG. 3B illustrates a schematic side view of a silicon substrate orwafer 2200 after diamond layer 2300 has been deposited thereon duringthe process for forming a diamond-silicon hybrid integrated heatspreader, according to an embodiment of this invention. The arrowscarrying the reference number 2310 represent the diamond film or diamondlayer 2300 being deposited onto the silicon substrate 2200. As mentionedpreviously, the diamond layer 2300 is a film formed by plasma-enhancedCVD. The silicon substrate wafer 2200 is placed in an environment or ina deposition chamber having a pressure of 20 to 50 Torr and atemperature of 800 to 1000° C. Process gasses are also placed into thedeposition chamber. The process gasses include methane at 0.5 to 5% andhydrogen. Plasma is activated using either a microwave CVD, andradio-frequency glow discharge, or a DC glow discharge, or a DC arc, orsimilar plasma activation technique. As mentioned previously, thedeposition rate of the diamond is from 10 to 50 microns per hour, andtherefore to form a film or diamond 100 microns thick takesapproximately 2 to 10 hours. Of course if a layer or film of diamond2300 is formed that is 200 microns thick the time for deposition will befrom 4 to 20 hours.

FIG. 3C illustrates a schematic side view of a silicon substrate wafer2200 with a diamond layer 2300 deposited thereon after a portion of thesilicon substrate 2200 has been removed. Also shown in FIG. 3C is agrinding wheel 300. The grinding wheel 300 is used to remove a portionof the silicon substrate 2200 from the wafer. In other words thegrinding wheel 300 is used to thin the silicon substrate 2200 to athickness in the range of 1 to 40 microns. In some embodiments the layerof silicon is thin to the range of 1 to 20 microns, and in still furtherembodiments the layer of silicon is thin to the range of 1 to 10microns. It has been found that a thin silicon layer 2200 does not havea significant impact on the thermal characteristics of thediamond-silicon hybrid head spreader 150. Therefore the grinding wheel300 is used to remove or thin the silicon substrate 2200 so that thesilicon layer 220 on the diamond-silicon hybrid integrated heat spreader150 will have a thickness that will not have a significant impact on thethermal characteristics of the integrated heat sink 150.

Advantageously, the silicon material 2200 of the silicon wafer can be aless expensive silicon, such as a polycrystalline silicon. This providesfor a less expensive integrated heat sink, and the silicon also allowsfor easier handling of the wafer-sized substrate 2200 during the processof forming individual heat sinks 150. Once the silicon substrate 2200 isthinned to a desirable thickness, the silicon substrate 2200, having adiamond layer 2300 thereon, can be diced or singulated to a size andshape approximately equal to the size and shape of a die 210 to whichthe diamond-silicon hybrid integrated heat spreader 150 will attach.

FIG. 4 is a graph of the junction-to-air thermal resistance of anintegrated circuit on a diamond silicon hybrid heat spreader versus thediamond layer thickness in microns for a diamond-silicon hybridintegrated heat spreader, according to an embodiment of this invention.The graph, shown in FIG. 4, includes a solid line 400 and diamond layerall by itself with a 2 micron thickness layer of silicon at the device.With a diamond layer of 100 microns in thickness, the junction-to-airthermal resistance is shown by point 402 on the solid line 400.Encircled on the graph are four other data points for diamond layerthickness of 100 microns. The four data points include thejunction-to-air thermal resistance for a substrate or silicon layer 220with a thickness of 4 microns as depicted by reference point 404. Asshown in FIG. 4, the thermal resistance or varying the distance ofdiamond from the power layer by 4 microns is approximately 0.52° C./W.Similarly point 410 shows the junction-to-air thermal resistance whenyou vary the distance of the diamond layer from the power layer by 10microns. Point 420 shows the impact of varying the distance of thediamond 230 layer from the power layer (back side surface 211 of the die210 as shown in FIG. 2) by 20 microns. Point 440 on the graph shows theimpact of varying the distance of the diamond layer 230 (as shown inFIG. 2) from the power layer by a distance of 40 microns. Thus as can beseen from FIG. 4, the thickness of the layer of silicon or the siliconsubstrate 220 (as shown in FIG. 2) does have an impact on the ability ofthe diamond to transfer heat. However, the impact is minimal or small atdistances from the power layer in the range from 2 to 40 microns.

FIG. 5 is a flow diagram 500 of the process for forming adiamond-silicon hybrid integrated heat spreader 150, according to anembodiment of this invention. The method 500 for forming a heatdissipating device or diamond-silicon hybrid heat spreader 150 includesplacing a layer of diamond on a silicon substrate 510, and thinning thesilicon substrate 512. Thinning the silicon substrate 512 includesgrinding a surface of the substrate. Placing a diamond layer onto thesilicon substrate 510 further includes depositing a diamond film ontothe substrate. Placing a diamond layer onto the silicon substrate 510further comprises depositing a diamond film onto the substrate usingchemical vapor deposition. The method 500 further includes dicing thesubstrate to form a plurality of heat dissipating devices 150 sized toform a thermally conductive connection to a die 514. The method 500 alsoincludes placing a surface of the silicon substrate 510 in thermalcommunication with a source of heat 516.

FIG. 6 illustrates a diamond-silicon hybrid integrated heat spreader 150attached to the die 210 of an integrated circuit 211, according toanother embodiment of this invention. The major components of thediamond-silicon hybrid integrated heat spreader 150 and the die 210 aresimilar to the diamond-silicon hybrid integrated heat spreader 150 andthe die 210 shown in FIG. 2. Accordingly the similar components of theinvention will not be discussed for the sake of clarity as well asbrevity. The discussion of FIG. 6 will, therefore, key in on thedifferences between the device shown in FIG. 2 and the device shown inFIG.6.

One of the differences is that the integrated heat spreader 150, whichincludes the layer of silicon 220, is directly bonded to the silicon ofthe surface 211 of the die 210. Direct bonding of silicon to siliconoccurs when two highly polished-flat silicon surfaces are brought intocontact. Bonding occurs due to the formation of Si—O—Si specie formedbetween the two silicon surfaces. This occurs as a result of the freesurface of silicon adsorbing OH radicals from the atmosphere accordingto the following reaction: Si—OH+OH—Si>H₂O+Si—O—Si. When the structureis heat treated, the oxygen from the H₂O forms SiO₂, and the hydrogendiffuses into the silicon. The bond strength increases with increasingheat treatment or annealing temperature. It has been found that attemperatures below 400° C., the bond strength between the silicon andsilicon is sufficiently strong for the direct bonding of the die to thediamond-silicon hybrid integrated heat spreader 150. It is necessary tokeep the temperatures below the point where the solder balls, such assolder balls 214 shown in FIG. 6, will melt or reflow.

FIG. 7 is a graph of the bonding strength of a silicon to silicon bondversus the bonding temperature according to an embodiment of thisinvention. FIG. 7 compares the silicon to silicon bond strength, whichis annealed at various temperatures, to the bond strength of a thermalinterface material. The thermal interface material is using a polymeradhesive such as Shinetsu 7756 polymer adhesive, which has a bondfracture strength of 1.5 to 2.5 Kg/cm². The bond strength is shown bythe bar 700 in the graph of FIG. 7. It can be seen that various bondingtemperatures used to anneal the silicon to silicon bond do not have tobe very large, such as approximately 25°, in order to have abond/fracture strength equal to the bond-fracture strength associatedwith the polymer thermal interface material 700. When the silicon tosilicon bond is annealed at 100° C., the bond-fracture strength isgreater than the bond-fracture strength associated with the polymerthermal interface material. At 200° C. anneal of a silicon to siliconbond, the bond fracture strength outperforms the polymer material.Similarly, the bond strength of the silicon to silicon bond forms a bond10 times stronger (at approximately 25 Kg/cm² ) when the bond isannealed at 300° C. than the bond-fracture strength associated with thepolymer thermal interface material. The bond strength of the silicon tosilicon bond is approximately 50 Kg/cm² when the silicon to silicon bondis annealed at slightly less than 400° C., which is also slightly lessthan the melting point of solder on leads in dies.

The use of a silicon to silicon bond has several advantages over the useof a thermal interface material for bonding the integrated heat sink 150to the die 210. Among the advantages is the elimination of a coefficientof thermal expansion mismatches. One of the common thermal interfacematerials is copper or copper cladding. Copper has a coefficient ofthermal expansion in the range of 15 to 17 parts per million per degreecentigrade. Diamond has a coefficient of thermal expansion of 1 to 2 PPMper degree centigrade, and silicon has a coefficient of thermalexpansion in the range of 3 to 4 PPM per degree centigrade. Thus, when asilicon to silicon bond is used to attach the diamond-silicon hybridintegral heat spreader 150 to a die 210, thermal interface material withthe highest coefficient of thermal expansion is removed. This leaves asilicon to silicon bond, both of which have the same thermal coefficientof expansion, and the layer of diamond attached to the substrate ofsilicon 220 that has a coefficient of thermal expansion which is muchcloser to the coefficient of thermal expansion of silicon. Theelimination of the thermal interface also eliminates the thermalresistances introduced by the thermal interface material and the twocontact resistances. The use of the diamond-silicon composite heatspreader results in significantly improved thermal performance as aresult of the significantly higher conductivity of diamond as comparedto copper.

An electronic device includes a die further having a first majorsurface, and a second major surface. The electronic device also includesa plurality of connectors associated with the first major surface of thedie, and an integrated heat spreader in thermally conductive relationwith the second major surface of the die. The integrated heat spreaderalso has a layer of silicon, and a layer of diamond attached to thelayer of silicon. The first major surface of the die attached to aprinted circuit board. In some embodiments, the layer of silicon is inthe range of 1 to 40 microns. In other embodiments, the layer of siliconis in the range of 1 to 20 microns, and in still further embodiments,the layer of silicon is in the range of 1 to 10 microns. In someembodiments, the layer of diamond is in the range of 50 to 400 microns.In other embodiments, the layer of diamond is in the range of 75 to 300microns, and in still further embodiments, the layer of diamond is inthe range of 100 to 200 microns.

The foregoing description of the specific embodiments reveals thegeneral nature of the invention sufficiently that others can, byapplying current knowledge, readily modify and/or adapt it for variousapplications without departing from the generic concept, and thereforesuch adaptations and modifications are intended to be comprehendedwithin the meaning and range of equivalents of the disclosedembodiments.

It is to be understood that the phraseology or terminology employedherein is for the purpose of description and not of limitation.Accordingly, the invention is intended to embrace all such alternatives,modifications, equivalents and variations as fall within the spirit andbroad scope of the appended claims.

1. A heat dissipation device comprising: a silicon substrate; and alayer of diamond attached to the silicon substrate.
 2. The heatdissipation device of claim 1 wherein the layer of diamond is depositedon the silicon substrate.
 3. The heat dissipation device of claim 1wherein the layer of diamond is a film of diamond deposited on thesilicon substrate.
 4. The heat dissipation device of claim 3 wherein thediamond layer has a thickness in the range of 100 to 200 microns.
 5. Theheat dissipation device of claim 3 wherein the diamond film is depositedon the silicon with a plasma enhanced chemical vapor deposition process.6. The heat dissipation device of claim 1 wherein a portion of thesilicon substrate is removed.
 7. The heat dissipation device of claim 1wherein a surface of the silicon substrate is ground smooth, the smoothsilicon surface opposite the diamond layer.
 8. The heat dissipationdevice of claim 1 further comprising a thermal interface layer incontact with a surface of the silicon opposite the diamond layer.
 9. Theheat dissipation device of claim 8 wherein the thermal interface layeris a metal.
 10. The heat dissipation device of claim 8 wherein thethermal interface layer is a thermal grease.
 11. The heat dissipationdevice of claim 1 further comprising a die in thermally conductiverelation with the surface of the silicon opposite the diamond layer. 12.The heat dissipation device of claim 11 wherein the die is attached tothe surface of the silicon opposite the diamond layer by silicon tosilicon direct bonding.
 13. The heat dissipation device of claim 11wherein the die is attached to the surface of the silicon opposite thediamond layer by a thermal interface material.
 14. The heat dissipationdevice of claim 11 further comprising a printed circuit board, whereinthe die is electrically coupled to a package.
 15. The heat dissipationdevice of claim 14 where the package is an organic land grid area. 16.The heat dissipation device of claim 1 wherein the silicon substrate hasa thickness in the range of 1 to 10 microns.
 17. An electronic devicecomprising: a die further comprising: a first major surface, and asecond major surface; a plurality of connectors associated with thefirst major surface of the die; and an integrated heat spreader inthermally conductive relation with the second major surface of the die,the integrated heat spreader further comprising: a layer of silicon; anda layer of diamond attached to the layer of silicon.
 18. The electronicdevice of claim 17 further comprising a printed circuit board, the firstmajor surface of the die attached to a printed circuit board.
 19. Theelectronic device of claim 17 wherein the layer of silicon is in therange of 1 to 40 microns.
 20. The electronic device of claim 17 whereinthe layer of silicon is in the range of 1 to 20 microns.
 21. Theelectronic device of claim 17 wherein the layer of silicon is in therange of 1 to 10 microns.
 22. The electronic device of claim 17 whereinthe layer of diamond is in the range of 50 to 400 microns.
 23. Theelectronic device of claim 17 wherein the layer of diamond is in therange of 75 to 300 microns.
 24. The electronic device of claim 17wherein the layer of diamond is in the range of 100 to 200 microns. 25.A heat spreader comprising: a silicon substrate; and a layer of diamondattached to the silicon substrate, wherein the silicon substrate has athickness to allow the layer of diamond to disappate heat at a ratesubstantially the same as the layer of diamond.
 26. The heat spreader ofclaim 25 wherein the layer of silicon is in the range of 1 to 40microns.
 27. The heat spreader of claim 25 wherein the layer of siliconis in the range of 1 to 20 microns.
 28. The heat spreader of claim 25wherein the layer of silicon is in the range of 1 to 10 microns.
 29. Theheat spreader of claim 25 wherein the layer of silicon is in the rangeof 2 to 50 microns.
 30. The heat spreader of claim 25 wherein the layerof diamond is a film of diamond deposited on the silicon substrate. 31.The heat dissipation device of claim 25 further comprising a thermalinterface layer in contact with a surface of the silicon opposite thediamond layer.